Remotely operated clamp

ABSTRACT

A clamp for detachably securing two structures together includes a clamp-supporting member movable on one structure and a clamp assembly carried by the supporting member. The clamp assembly includes a clamp body rigidly supporting a clamp element, and a spring for urging the body to a first position relative to the support member. The supporting member is moved to engage the clamping element with a clamp surface on the other structure and to deflect the spring whereby the clamp element and clamp surface are urged together under the force of the deflected spring. The supporting member is manually operated and readily accessible.

United States Patent Clifford L. Barnes m m m m e m m m m m "mu" "n mn m & m m a m M n h mM" .H n L u an a n mmum m m CJCS V1306 R O 3566 H 9999 a ll, nlt 380 ma 1 mw mam E ,3 W 6759 m 9452 m HU 223 PA Q m 0 .m m 1mm k 07 h r m ww C az mm k4 P5 d A1moww 0. de m N w m n .L e emfl V pq as .m AFPA l 1.11] 2 253 7 2247 l [rill s 8v.v. a mmnmdn nwn u ioom o te bP D. c W n Pws P mw m m m s .0 cc ac 0 02 m h m .mm C m .2. c. m r. 2 8 u Jun 0 :1 SW. m Pd ABSTRACT: A clamp for detachably securin together includes a clamp-supporting mem one structure and a clamp assembly carried by the su member. The clamp assembly includes a clam clamp element tion relative to the support member. is moved to engage the clamping el clamp surface on the other structure and to deflect the whereby the clamp element and clam together under the force of the deflecte ing member is manually operated and readily accessible.

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1 REMOTELY OPERATED CLAMP BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates to clamps and more particularly relates to remotely operated clamps for detachably securing two structures together.

2 The Prior Art The prior art has proposed clamps for securing structures together at locations which are not easily accessible. The connection of foundry pattern boards to pattern frames is one example of structures which are connected together at relatively inaccessible locations. In the past, pattern boards were attached to the pattern frames by clip and wedge units. Generally the clip and wedge units were located at the juncture of the pattern frame and board so that access to these units was had only through the pattern frame itself.

The locations and operation of these clamping units therefore required otherwise unnecessary manipulations of the pattern board and frame in order to assemble and disassemble them. The clamping devices used to hold the pattern frame to the pattern board were required to be sufficiently strong to withstand vibrational forces applied to the frame and board as well as to support the direct load of the pattern board on the pattern frame. Furthermore, the clamping tension had to be suflicient to overcome camber or warpage of the pattern board, resulting from age or improper handling,to assure proper seating of the board on the frame.

Clamping pattern boards to pattern frames is exemplary of environments in which it is necessary to clamp structures together at relatively inaccessible locations; in which the clamping device may be subject to vibrational and/or direct loads; and in which the clamping force must be relatively great. Other environments having one or more of the abovenoted characteristics exist in which clamps are, or may be, used to detachably secure parts together.

The prior art proposals attempting to provide clamps for use in such environments have not adequately dealt with the problems outlined either because of the difiiculty in operating the clamps, inability of the clamps to remain effective under loads, insufficient clamping forces, or combinations of these inadequacies.

Summary of the Invention The present invention provides a new and improved clamp which: (I is remotely operable for exerting clamping forces at inaccessible locations; (2 maintains adequate clamping forces even under vibrational or direct loads, or both; and, (3 is capable of exerting relatively large clamping forces.

The new clamp is effective to detachably clamp two structures together and includes a clamp assembly supported on a rotatable shaft mounted in one of the structures. The supporting shaft includes an eccentric or ofi'set portion upon which the clamp assembly is carried.

The clamping assembly includes a body which is mounted upon the eccentric portion of the shaft, a clamp element including a force applying or reaction surface engageable with the other structure, and a biasing assembly between the eccentric portion of the shaft and the body.

When the supporting shaft is rotated, the reaction surface engages the other structure preventing the clamp assembly from rotation with the shaft. The eccentric shaft portion orbits about the axis of rotation of the shaft to deflect a spring in the biasing assembly. This causes the reaction surface to firmly engage the other structure by a clamping force equal to the spring force.

An end of the operating shaft is easily accessible to an operator and the shaft is manually rotated to operate the clamp to secure the structures together. By turning the supporting shaft in the opposite rotational direction, the clamp element is disengaged from the other structure so that the structures are separable. Since the clamp is operated by manipulation of its supporting shaft, the clamp can be located at inaccessible locations yet is easily clamped and declamped by manually turning the shaft. The spring loading on the clamping surfaces insures against the clamp being loosened under vibratory or direct loads The clamping force developed by the new clamp is limited only by the strength of the parts used to construct the clamp. The shaft is rotatable by use of a tool which can exert large torques on the shaft. The eccentric shaft portion acts on the spring through a small lever arm so that the manual tool has a relatively great mechanical advantage and the spring can have a correspondingly large spring rate.

A principal object of the present invention is the provision of a new and improved clamp effective to detachably connect two structures at a location inaccessible to an operator and which is of simple construction, operable by the operator at a location remote from the clamp, maintains the clamped structures secured together under vibrational and/or direct loads and which is capable of exerting extremely large clamping forces.

Other objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment made with reference to the accompanying drawings which form a part of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a pattern board and pattern frame which are detachably secured together by clamps embodying the present invention;

FIG. 2 is a perspective view of a clamp embodying the invention;

FIG. 3 is an exploded perspective view of a portion of the clamp shown in FIG. 2;

FIG. 4 is an elevational view, partly in cross section, of a clamp shown in one operative position;

FIG. 5 is a view similar to FIG. 4 showing the clamp in another position;

FIG. 6 is a view similar to FIG. 4 showing the clamp in still another position; and,

FIG. 7 is an elevational view similar to FIG. 4 showing the clamp in a clamping position.

DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 1 illustrates a number of holddown clamps l0 embodying the present invention which are assembled for detachably connecting a pattern board structure 11 to a pattern frame structure 12. While a pattern board and frame are illustrated in connection with the clamps 10, these clamps are usable in connection with any structures which are detachably connectable. For the noted reasons the pattern board and pattern frame are not described in detail and may be of any suitable construction. The pattern board carries a series of elements 14 each of which cooperates with an individual holddown clamp 10 for clamping the pattern board to the frame.

The clamps 10 are identical and accordingly only one clamp is illustrated and described in detail. Referring now to FIG. 2, the clamp 10 includes a clamp assembly 21 carried on a supporting shaft 12 which shaft is rotatably mounted in the pattern 12. A clamp element 14 is connected to the pattern board 11 at a position which registers with the location of the clamp 10 when the pattern board and frame are properly assembled. The shaft 22 is then rotated causing the clamp; assembly 21 to engage the element 14 and secure the pattern board to the pattern frame. Rotation of the shaft 22 in the opposite rotational direction disengages the assembly 21 from the element 14.

The shaft 22 is rotatably supported by spaced frame structures 25, 26 in the pattern frame 12. The shaft 22 is rotatable about a rotation axis 27 extending through the assembly 21. The shaft includes an eccentric portion 30, preferably formed by an offset in the shaft between its ends. The offset is cylindrical and has a centerline 300 which is parallel to and spaced from the rotation axis 27. AS the shaft rotated, the centerline 30a orbits about the axis 27.

The frame 25 is provided with spaced stops 31, 32 and shaft 22 carries a lug 34 which projects from the shaft between the stops 31 and 32. The lug 34 is engageable with each stop to define the limits of rotational movement of the shaft.

The shafi 22 is manually rotated by an operator at a location remote from the clamp assembly. For this purpose, an end 35 of the shaft extends through the frame member 26 and carries a radially projecting pin 36. The pin is engaged by a handtool by which the shaft 22 is rotated. Preferably, the tool provides a lever arm for turning the shaft which is considerably larger than the distance between the centerline 30a and the rotation axis 27. The tool may be of any suitable construction and therefore is not illustrated or described.

The clamp assembly 21 is supported on the offset portion 30 so that when the shaft 22 rotates the assembly moves about the axis of rotation 27. The assembly 21 includes a clamp body 40 a hooklike clamp element 42, and a biasing assembly 44. The body 40 is a rigid tubular member, preferably cylindrical, having parallel, diametrically spaced slots 46, 47 extending axially along it. The slots 46, 47 are identical and each includes parallel side surfaces 48, 50 and a semicircular end surface 52. The eccentric portion of the shaft 30 extends through the slots 46, 47 transversely of the body 40. The surfaces 48 and 50 of each slot are spaced sufficiently far apart to slidably receive the cylindrical offset section 30 of the shaft. Similarly, the semicircular end 52 has a radius curvature which is at least as large as the radius of the offset portion 30 so that the offset is slidable in the body.

The clamp element 42 includes a base 54 attached to an annular end surface 55 of the body and a hook 57 defining a reaction or force-applying surface 60. The element 42 may also include a flat 62 facing away from the hook for a purpose which is described presently.

The biasing assembly 44 functions to bias the body 40 to a position in which the offset 30 seats on the end surface 52 of the slots 46, 47. The assembly 44 includes a helical compression spring 64, a washer 66 and a pin 68. The spring 64 is disposed in the body, with one end seated against the washer 66. The washer is maintained in place by the cotter pin 68 which extends through the body. The opposite end of the spring seats against the offset portion 30 of the shaft. The spring 64 is compressed between the washer 66 and offset 30 and thus reacts against the washer to maintain the offset 30 seated against the semicircular end 52 of the slots 46, 47.

The elements 14 on the pattern board are preferably straplike members each defining a reaction surface 72 which is spaced from the pattern board a sufficient distance to permit entry of the hook 57 between the surface 72 and the pattern board. The elements 14 are rigidly secured to the pattern board.

The operation of the clamp embodying the present invention is apparent from FIGS. 4-7 which illustrate successive positions of the clamp 10 as a pattern board is secured to a pattern frame.

As is seen in FIG. 4, the shaft 22 is rotated in a clockwise direction to its limit position at which the lug 34 engages the stop 31. In this position the hook 57 is located so that the pattern board 1 1 is readily placed flush upon the pattern frame 12 without interference between the element 14 and the book.

When the pattern board 1 1 is registered with the frame, the shaft 22 is turned counterclockwise (as viewed in FIGS. 4-7) to clamp the board to the frame. As noted previously, the spring 64 urges the body 40 into engagement with the offset 30 at the end 52 of the slots. The engaging force provides sufficient friction between the body and the offset shaft portion to assure that the clamp assembly 21 turns with the shaft. As the shaft turns counterclockwise, the hook 57 advances into the element 14 so that the reaction surfaces 60, 72 confront each other (FIG. 5).

Continued counterclockwise rotation of the shaft 22 engages the hook 57 and the element 14. The resistance to motion of the hook 57 created by engagement with the element 14 overcomes the frictional force maintaining the body 40 fixed with respect to the offset 30. Accordingly, as the shaft continues to turn, the offset 30 rotates and slides in the body 40.

As the offset 30 moves away from the elements 14, the engaged reaction surfaces 60, 72 prevent movement of the assembly 21 away from the elements 14 with the offset 30. The offset 30 thus moves out of the end 52 of the slots compressing the spring 64 between the washer 66 and the offset 30. The spring compression force is applied to the reaction surface on the element 14 by the hook to provide the clamping force between the pattern board and frame.

FIG. 6 illustrates the relative positions between the shaft, offset and clamp assembly 21 when the shaft is rotated 90 from the position illustrated in FIG. 5. During the 90 shaft rotation between the FIG. 5 position and FIG. 6 position, the spring 64 is deflected a distance equal to the distance between the axis of rotation 27 and the centerline 30a of the offset shaft portion 30.

Continued shaft rotation in a counterclockwise direction orhits the centerline 300 about the axis 27 to produce a maximum spring deflection equal to twice the distance between the axis of rotation 27 and the centerline 30a. This position of the offset 30 relative to the body 40 and spring 64 is shown in FIG. 7. In this condition of the clamp 10, the spring force is maximum and hence the clamping force between the pattern board and frame are maximum. In the FIG. 7 position, the lug 34 on the shaft engages the stop 32 to limit further counterclockwise rotation of the shaft 22. The centerline of the offset shaft portion 30 is aligned with the axis of rotation 27 of the shaft 22 and accordingly the spring force exerted on the offset portion acts through the rotation axis 27. This prevents the shaft 22 from being rotated clockwise by the spring force applied to the offset 30.

When it is desired to disengage the hook 57 from the element 14, the shaft 22 is manually turned in a clockwise direction. This orbits the centerline 30a clockwise about the rotation axis 27, relieving the spring compression force. As the spring force is alleviated, the clamping force between the reaction surfaces 60, 72 is gradually relieved. When the offset 30 engages the slot surfaces 52, the frictional force between the offset and the body 40 is reinstated and the body 40 turns with the shaft 22. The hook 57 then moves out of the element 14 enabling the pattern board to be removed from the frame.

In order to assure that the body 40 is properly aligned with the shaft 22 for a succeeding clamping operation, a stop may be provided for engagement with the flat 62 on the hook. The flat 62 engages the stop 80 and prevents movement of the body 40 with the shaft 22 as the shaft moves clockwise. When the shaft 22 reaches its limit of clockwise rotation, the body 40 and shaft 22 are properly positioned with respect to each other for the succeeding clamping operation (see FIG. 4). The stops 80 are not essential since the clamp assemblies 21 may be appropriately positioned manually on the shaft 22 before each clamping operation.

While a single preferred embodiment is illustrated and described in considerable detail, it should be apparent to those skilled in the art that various modifications, adaptations and uses of a clamp embodying the invention can be made without departing from the invention. For example, a clamping assembly 21 might be provided with a reaction surface at the end of the body 40 adjacent the cotter pin 68. In such a modified apparatus, a clamping force is exerted away from the end of the body 40 adjacent the cotter pin 68. Other modifications, adaptations and uses of the new clamp may occur to those skilled in the art and it is intended to cover hereby all adaptations, modifications and uses which come within the ambit of the invention.

What is claimed is:

1. In a clamp for detachably securing first and second structures together:

a. a clamp assembly;

b. a support member movably supported by one of said first and second structures and carrying said clamp assembly; and,

c. said clamp assembly comprising l. a clamp body supported by said support member for movement between first and second positions relative to said support member;

. a clamping force transmitting surface defined on said clamp body, said surface engageable with said other structure to transmit clamping force between said other structure and said clamp body, said surface being fixed against movement relative to said clamp body;

3. biasing means between said clamp body and said support member for urging said body toward said first position and,

. at least a guide surface on said clamp body engaging said support member and guiding movement of said clamp body relative to said support member against the force of said biasing means to said second position;

5. said clamping surface of said clamp body urged into engagement with said other structure by said biasing means when said clamp body is in said second position.

Zrln a clamp for detachably securing first and second structures together;

a. a clamp assembly;

b. a support member comprising a shaft movably supported by one structure for rotation about an axis and carrying said clamp assembly, said shaft having an eccentric surface; and,

c. said clamp assembly including:

1. a clamp element having a surface engageable with said other structure;

2. a clamp body rigidly supporting said clamp element;

3. biasing means comprising a spring member between said body and said shaft for urging said body to a first position relative to said shaft, said spring member having one end reacting against said body and another end reacting against said eccentric surface of said shaft;

4. at least a guide surface defined by an elongate slot in said clamp body for guiding movement of said body relative to said shaft against the force of said biasing means to a second position, said eccentric surface of said shaft extending through said slot; and,

5. said surface of said clamp element urged into engagement with said other structure by said biasing means when said body is in said second position.

3. 'A clamp as claimed in claim 1 wherein said clamp support member comprises a shaft supported by said one structure for rotation about an axis, said shaft having an eccentric surface engageable with said at least one guide surface.

4. A clamp as claimed in claim 2 wherein said eccentric surface is rotatable about said axis relative to said clamp body and effective to compress said spring during relative rotation when said clamping surface engages a surface to be clamped, said clamping surface and said clamped surface urged together by said spring.

5. A clamp for detachably securing first and second structures together comprising:

a. an operating member supported on one of said structures for rotation about an axis;

b. at least a part of said member orbitally movable about said rotation axis;

c. a clamp body slidably supported on said part of said member;

(1. a clamping force reaction surface defined on said clamp body, said reaction surface engageable with a surface on the other of said structures for transmitting clamping force between the structures;

e. a spring between said body and said part of said member for urging said body to a predetermined position relative to said part;

f. said operating member rotated to move said reaction surface to engage said surface of said other structure to prevent movement of said clamp body relative to said other structure, said part of said member thereafter moving relative to said body to compress said spring whereby said reaction surface is urged into clamping engagement with said surface of said other structure by the spring force. 6. A clamp as claimed in claim 5 wherein said clamp body comprises a tubular member having surfaces slidably engageable with said part, said spring supported within said tubular member and bearing against said part of said member.

7. A clamp as claimed in claim 6 and further including at least one stop member fixed to said one structure and engageable with a stop member on said support member to limit movement of said support member relative to said clamp body when said reaction surface is in engagement with said other structure. 

1. In a clamp for detachably securing first and second structures together: a. a clamp assembly; b. a support member movably supported by one of said first and second structures and carrying said clamp assembly; and, c. said clamp assembly comprising
 1. a clamp body supported by said support member for movement between first and second positions relative to said support member;
 2. a clamping force transmitting surface defined on said clamp body, said surface engageable with said other structure to transmit clamping force between said other structure and said clamp body, said surface being fixed against movement relative to said clamp body;
 3. biasing means between said clamp body and said support member for urging said body toward said first position and,
 4. at least a guide surface on said clamp body engaging said support member and guiding movement of said clamp body relative to said support member against the force of said biasing means to said second position;
 5. said clamping surface of said clamp body urged into engagement with said other structure by said biasing means when said clamp body is in said second position.
 2. a clamping force transmitting surface defined on said clamp body, said surface engageable with said other structure to transmit clamping force between said other structure and said clamp body, said surface being fixed against movement relative to said clamp body;
 2. In a clamp for detachably securing first and second structures together; a. a clamp assembly; b. a support member comprising a shaft movably supported by one structure for rotation about an axis and carrying said clamp assembly, said shaft having an eccentric surface; and, c. said clamp assembly including:
 2. a clamp body rigidly supporting said clamp element;
 3. biasing means comprising a spring member between said body and said shaft for urging said body to a first position relative to said shaft, said spring member having one end reacting against said body and another end reacting against said eccentric surface of said shaft;
 3. biasing means between said clamp body and said support member for urging said body toward said first position and,
 3. A clamp as claimed in claim 1 wherein said clamp support member comprises a shaft supported by said one structure for rotation about an axis, said shaft having an eccentric surface engageable with said at least one guide surface.
 4. A clamp as claimed in claim 2 wherein said eccentric surface is rotatable about said axis relative to said clamp body and effective to compRess said spring during relative rotation when said clamping surface engages a surface to be clamped, said clamping surface and said clamped surface urged together by said spring.
 4. at least a guide surface on said clamp body engaging said support member and guiding movement of said clamp body relative to said support member against the force of said biasing means to said second position;
 4. at least a guide surface defined by an elongate slot in said clamp body for guiding movement of said body relative to said shaft against the force of said biasing means to a second position, said eccentric surface of said shaft extending through said slot; and,
 5. said surface of said clamp element urged into engagement with said other structure by said biasing means when said body is in said second position.
 5. said clamping surface of said clamp body urged into engagement with said other structure by said biasing means when said clamp body is in said second position.
 5. A clamp for detachably securing first and second structures together comprising: a. an operating member supported on one of said structures for rotation about an axis; b. at least a part of said member orbitally movable about said rotation axis; c. a clamp body slidably supported on said part of said member; d. a clamping force reaction surface defined on said clamp body, said reaction surface engageable with a surface on the other of said structures for transmitting clamping force between the structures; e. a spring between said body and said part of said member for urging said body to a predetermined position relative to said part; f. said operating member rotated to move said reaction surface to engage said surface of said other structure to prevent movement of said clamp body relative to said other structure, said part of said member thereafter moving relative to said body to compress said spring whereby said reaction surface is urged into clamping engagement with said surface of said other structure by the spring force.
 6. A clamp as claimed in claim 5 wherein said clamp body comprises a tubular member having surfaces slidably engageable with said part, said spring supported within said tubular member and bearing against said part of said member.
 7. A clamp as claimed in claim 6 and further including at least one stop member fixed to said one structure and engageable with a stop member on said support member to limit movement of said support member relative to said clamp body when said reaction surface is in engagement with said other structure. 